Firing mechanism



AP' 18, 1950 w. sUMMERBl-:LL a-rAL 2,504,162

FIRING MECHANISM Filed July ),O, 1945 5 Sheets-Sheet 1 April 18, 1950 w. suMMERBELL ETAL 2,504,162

FIRING MECHANISM Filed July 10, 1945 5 Sheets-Sheet 2 ly/llllllllll]- APrll 18, 1950 w. suMMl-:RBELL ETAL 2,504,162

FIRING MECHANISM Filed July 10, 1945 Z5 Sheets-Sheet 3 3 vwa/Mow Willian-1 E umm Erb au Lnui J. Rh ein.

Patented Apr. 18 1950 FIRING MECHANISM William Summerbell, Washington, D. C., Louis J. Rhein, Aberdeen, Md., and Owen D. Hoopes, Arlington, Va.; Edith May Summerbell executrix of said William Summerbell, deceased Application July V1o, 1945, serai No. 604,286

(c1. ssi-27) (Granted under the act of March 3, 1883, as

amended April 30, 1928; 370 O. G. 757) 4 Claims.

The invention described herein may be manufactored and used by or for the Government for governmental purposes, without the payment to us of any royalty thereon.

This invention relates to ring mechanisms.

A purpose of the invention is to provide a ring mechanism for artillery employing separate loading ammunition and in which a separate primer is used to ignite the propellant charge each time the gun is fired.

Another purpose of the invention is to provide a simple and convenient means of inserting into and removing a primer cartridge from the breech mechanism of a gun.

A further purpose of the invention is to provide a means of automatically removing the red primer cartridge.

An additional purpose of the invention is to provide a firing mechanism which prevents the escape of gases through the firing mechanism.

Another purpose of the invention is to provide a means of applying a uniform and predetermined degree of ring pin impact against the primer cartridge regardless of the amount of force applied to the firing lanyard, and for cocking and firing the mechanism upon a continuous pull of the lanyard.

Other purposes and advantages of the invention will become apparent from the following description of a preferred device embodying the invention and the drawings thereof in which:

Figure 1 is a face view of the device in firing position;

Figure 2 is a face view of the device with open breech;

Figure 3 is a side sectional View of the device taken upon a plane indicated by the line 3-3 of Fig. 1;

Figure 4 is a plan View taken along line 4-4 of Figure 3 and partly in section to indicate the internal structure of the movable housing;

Figure 5 is a sectional view taken along line 5-5 of Figure 3;

Figure 6 is a sectional view taken along line E- of Figure 3;

Figure 7 is a side elevational view of the firing mechanism, the view being partly broken out along line 1-1 of Figure 4;

Figure 8 is a detail longitudinal sectional view of the ring hammer and tiring spring stop taken in a plane indicated by line 8 8 of Fig. l0;

Figure 9 is an end View looking from the right, Fig. 8.

Figure 10 is a detail top view of the iiring hammer and firing spring stop;

Figure 11 is a face view taken along line l I-l I of Figure '7, showing only the surfaces nearest line H-ll;

Fig. 12 is an exploded perspective view of the hammer and trigger assembly and their housing.

Fig. 13 is a section taken upon a plane identified by the line I3|3, Fig. 3, and

Fig. 14 is an enlarged sectional view of a portion of Fig. 3.

As will be more fully explained below, the present invention provides a ring mechanism, no part of which needs to be removed from the gun to remove a red primer or to insert a new primer in preparation for again ring the gun. The firing mechanism may, for convenience of description, be considered as having several main \mechanical operations or operating parts which in turn cooperate to cause the mechanism to function as a unitary whole.

Thus, there is the function or operation of ejecting the red primer cartridge. There is the operation of opening and closing the breech of the ring mechanism which is accomplished mainly by lowering or raising the movable breech block of the mechanism. There is the operation of firing the primer by a continuous pull on the lanyard, thus cooking the mechanism, retracting the driving spring and then releasing it so it can cause the striker to actuate the ring pin, ring the primer.

There is provision for automatically adjusting the primer head space and in which the mechanism` will not move to firing position until the head space is properly adjusted, thereby guarding against damage caused by improper headspace.

In addition there is provision for providing a standardized impact against the primer regardless of the force used in retracting the lanyard, and also provision for allowing the cooking lever to which the lanyard is attached, to be rotated to any one of a number of angular positions throughout a complete circle so the direction of pull of the lanyard may be thus adapted to the gunners needs.

Reference is now had to the drawings in which there is a breechblock carrier indicated generally at I G and designed for carrying a breechblock for closing the breech end of a gun barrel bore. An obturator spindle l2 has a central ash passageway i4 leading at its forward end, not shown, to the inside of the breech end of the barrel bore of the gun where the separate loading propellant "charge is normally placed.

The spindle I2 extends rearwardly through a central bore It (Fig. 4) in carrier l0, said bore I6 being enlarged at I8 and further enlarged at 20. A firing mechanism housing 22, generally circular in external contour, is located in bores I8 and 2li, a substantially annular adapter ring 2 being employed to take up the otherwise empty space which, in some guns, may remain in bore 20 outside of the housing 22. The adapter ring 24 is split at 23 and is secured to carrier I0 by means of screws 25.

The obturator spindle l2 has external threads 26 at its rearward end 28 which engage the enlarged threaded forward portion 30 of central bore 32 of housing 22, said portion 3l! being located in the forward portion 33 of housing 22.

The housing 22 has e, reduced outside diameter at 35, thus forming with bore I8 of carrier lll a substantially annular chamber` 3E in. which is located a compression spring 33. The housing 22 being threadably secured to the rearward end of obturator spindle i2 which is necessarily slightly movable longitudinally upon ring the gun, is thus slidably located in bore i8.

' An obturator spindle plugV so, having an enlarged4 shoulder or collar t2 is threaded at its forward end [i4 into arecess 46 in the rearward end of obturator spindle I2. An annular copper gasket 48 is located between the forward end of plug l0 and the inner forward end of recess 46 for effecting a tight seal against gases escaping around the outside of plug 49. The flat surfaces of the washer 43 are also engaged and pressed into by circular projections V-shaped in crosssection in the abutting surfaces of plug 4E) and recess l which further enhance the sealing ef- 1 fect of the washer i8 as clearly illustrated in Fig. 14. The further details of construction of spindle plug t and its baille member 5l] are described in detail in our Copending Patent 2,428,398, dated October 7, 1947.

The central bore 32 of housing 22 is reduced at 52 for receiving the shoulder 42 of plug fil), and is further reduced at 5B. The rearward portion 56 of plug Gil extends through the bore 54 but does not touch the walls of the bore, thus leaving an annular recess 58 between the walls of bore 54 and portion 56 of the plug lil in which is slidably located a primer holder and extractor '60 whichv is generally a hollow cylinder in shape.

The extractor Gil has an enlarged central bore "62 which slopes inwardly from locations 611 to 66,

thereby conforming to the external contour of rearward portion- 56 of' plug G0. Extractor G0 is provided with an upwardly projecting key 68 which slides in a keyway 'l0 formed in the corresponding portion of bore 52. The bore B2 slopes outwardly from locations 66 to 72, forming a sloping support for the corresponding surface of the rim of a primer cartridge 'i3 to be inserted therein, the primer 'I3 extending into the central bore 14 of plug to. The primer 131s rmly rammed into the bore 'M by means of pressure exerted on it by face plate 76 which is carried into the position shown in Figure 3 by means which will be described below.

By examination of Figure 3, it will be noted that a. portion of the primer 13 also rests on the reduced rearward end surface i8 of spindle plug 40. Thus, to be sure that there is no looseness or play of the primer cartridge 13 between those abutting parts, including face plate 76, which are to support it in place, the spindle plug'd must be properly located as shown iny 'Figure 3 which shows the. position of the various parts for correct head- '4 space. Thus the shoulder 42 of plug 40 must be in contact with the surface of bore 52.

Tc be sure that the spindle plug 40 is properly positioned before the gun can be red, a head space safety member 82 (Figs. 3 and 6) is provided. The member 82 is generally cylindrical in shape, having an enlarged cylindrical upper portion Sri, a converging portion 86 with sloping sides, and a reduced cylindrical lower portion 88. The safety member 82 is slidably disposed in a vertical recess all formed in housing 22 and extends radially inward from the housing circumference to location 92 where it intersects with and opens upon keyway 70. The round recess 9 has vertical upper side walls extending from locations 94 to 95, which are slightly longer than the vertical length of portion 84 of safety member 82. The recess then slopes inwardly from locations 96 to 98` and then is cylindrical again but only large enough to allow reducedportion 88 of safety member 32 to pass through. As may be seen in Figure 6, the safety member 82 will, if unsupported, drop until its sloping portion 86 is in contact with the sloping portion of recess extending from locations 96 to 98, at which time the lower portion 88 of the safety would be extending downwardly into keyway lil and would thus be in the way of and prevent the movement through the keyway, of key 68 on extractor Sii, as may also be seen in Figure 3.

Hence it is apparent that for the extractor 5@ to move as far forwardly against spindle plug i0 as is necessary, its key 68 must not be obstructed by portion S8 of safety 82, that is, the safety 82 must be elevatedto the position shown in Figures 3 and 6 so portion 88 does not extend into keyway l at all.

To elevate portion 8S to the requisite height, the relative dimensions of safety member 82 and shoulder 2 of spindle .plug 4i) are so arranged that when the corner l of shoulder '42 bears against sloping portion 86 of safety 82 it raises the safety portion 88 out of keyway 70 only when the spindle plug is in correct location as shown in Figure 3 for proper headspace.

As shown in Figure 3, headspace safety 82 has a recess |62 in which is disposed' a compression spring l f which has its lower end pressing down on the base of recess H62 and its upper end confined by plug It which is threaded into the upper enlarged portion Hi8 of recess 9G. The effect of spring |04 is to continuously press safety member 82 downward. Thus, if spindle plug 4U is moved forwardly, and extractor 6G is retracted to the rear, safety 82 is pressed downward inte keyway 'lll and prevents the key 68 and hence the extractor 63, from moving forward. If the extractor 60 cannot move forward, as will be further explainedV below, it will prevent moving the face plate I6 and its firing pin into ring position and the gun cannot then be fired. The construction just described is covered by our copending divisional application, Serial Number 7 6,742, nled February 16, 19419, forF'iring mechanism.

The face plate 76 is carried by a movable firing lock housing or body H6 carried on housing 22 and which acts as a small breechblock. A pin 77 serves to secure plate'lt to housing HB. The housing li carrying the elements comprising the firing assembly, is arranged for reciprocal movement between the firing position shown in Figure 1, and the position shown in Figure 2 where the fired primer has been extracted and the primer chamber is uncovered. The rearward portion of the housing 22 has a central vertical channel I l2 in which the forward portion ||4 of housing fits for guided vertical movement. Channel H2 has generally vertical ribs |28 and |30 which slidably t corresponding grooves |24 and |25 in housing H0.

As illustrated in Figure '7 in connection with groove |28 and its rib |30, all grooves and ribs are inclined downwardly and rearwardly. The result is that as movable housing ||8 is dropped from the ring position shown in Figures 1, 3 and 7, to the open position shown in Figure 2, the housing H0 is also moved rearwardly by these inclined guide members.

As shown inFigures 3 and 7, face plate 76 has a sloping surface at |32 which cams the primer A73 into its desired location with its head supported by the extractor and by the end surface 78 of the spindle plug, and its cylindrical sides rammed firmly into the bore 74 as illustrated. As the primer 73 is thus cammed into position, the same pressure presses the extractor 60 into its forwardmost position.

A rng pin |34 is slidably disposed in a firing pin bore |36 extending through face plate 78 and rearwardly through a portion of movable housing ||0. The rearward portion of said bore is reduced at |38, providing a stop for engaging collar |48 on the ring pin and preventing the rearward motion of the firing pin beyond the position shown in Figure 3. The rearward end |42 projects into a recess 44 in housing ||0. A firing pin spring |48 serves to yieldingly maintain firing pin |34 in retracted position except when momentarily driven forward when struck by the nose |48 of hammer |82, the reduced forward end |50 then moving forward and striking the 4primer 73, firing it.

The extractor 88 is provided with two lugs |52 (see Fig. 5), the forward surfaces |54 of which are in slidable contact with cam surfaces |56 on movable housing |63, as seen in Figure '7. When the gun is red, and the housing ||0 is dropped from the position shown in Figure l to that shown in Figure 2, the lugs |52 are cammed rearwardly by the sloping portion |58 of cam surfaces |56, causing the extractor to be sharply moved rearwardly, thus throwing out or ejecting the fired primer cartridge 78 through the U-shaped passageway |88 formed in the upper surface of movable housing i8. The lugs |52 strike against the sloping surface |32 on movable housing ||0 thus preventing the extractor from being ejected along with the fired primer cartridge.

As particularly illustrated in Figure 3, the movable housing il! has a generally cylindrical recess |84 axialiy aligned with the bore |38 containing the firing pin |34. The recess |84 has a forward reduced portion |44 into which the rearward end |42 of the firing pin |34 projects. The recess |84 also has an intermediate slightly enlarged portion |88 andl a rearward threaded portion |88 slightly larger in diameter than portion |88. A locking cap |70 is threaded into portion |58 and serves to close the recess |64 at its rearward end. The cap |78 has both a projecting rib |72 and a surface slot |74 so it may be turned by hand, or with the aid of either a pliers gripping the rib or a screwdriver or coin inserted into the slot. The locking cap |78 has a recess |76 formed in its inner face in which is seated the rearward end of a ring spring |78, the forward end of which extends into a recess |80 formed in a hammer or striker |82, and bears against the rearward face of a 'firing spring stop |84. As is seen in Vthe detail drawings in Fgures .8, 9 and l0, the

hammer |82 has an enlarged rearward portion |88 smoothly tting recess |86 and a forward portion |88 smoothly fitting recess |44. The forward portion |88 of hammer |82 is out away at |90 and |82, forming two parallel side surfaces for a portion of its length so that two openings |94 and |96 are made in the forward end of recess |80. The stop |84 has two forward extensions |98 and 200 extending through the openings |94 and |96, which are long enough to extend forwardly beyond the nose |48 of hammer |82.

It will thus be noted in Figure 3 that the ring spring |78 is constantly under compression between cap |78 and stop |84, the forward ends of extensions |98 and 20|! being normally held against the forward end surface 288 of recess |44. It will also be noted that there is normally some clearance between thenose |48 and the rearward end |42 of the firing pin |34. y

A bore 2|2 closed at its forward end by a plug 2|7 is formed in movable housing |||J parallel to and laterally offset from recess |64. The bore 2 |2 contains the forward portion of a trigger assembly, the rearward portion of which extends rearwardly out of said bore as shown in Figure 3. The trigger assembly has the function of retracting the hammer |82 and the firing spring stop |84, the firing spring |78 being thereby compressed against cap |70. After the spring is thus compressed to a suitable degree, the trigger assembly releases the spring |78 to force the firing spring stop |84 and the hammer |82 forwardly toward the firing pin |34.

A pull rod 2|4 has its forward end enlarged and divided into a fork or clevis 2|G between the prongs of which is pivotally arranged a firing hammer tripper 2|8, the pivot pin being located at 220. A bushing 222 is carried by the forward end of pull rod 2|4, keeping it centered in bore 2|2. The inner bore of bushing 222 is reduced at its rearward end 224 so as to prevent forward movement of the bushing 222 past the shoulder 228 formed on pull rod 2|4. A hollow bushing-like member 228 is threaded into the rearward end of bore 2|2 at 238 and has a central bore 232 in the reduced forward portion 234 of which the rearward portion of pull rod 2|4 is slidably disposed.

The bore 232 is enlarged at 238 and further enlarged at 238. A bushing 240 has its forward reduced portion 242 slidably disposed in bore 236 and its rearward portion 244 siidably disposed in bore 238.

Bushing 248 has a bore appreciably greater in diameter than the adjacent rearward portion of pull rod 2|4, said bore being enlarged at 248 to loosely receive an annular washer 248 through which the rod 2 I4 extends. is prevented from pulling forwardly out of' washer 248 by any suitable means such as a cotter pin passing transversely through a hole in its rearwardly protruding end. Or the end of rodv 2|4 may have a transverse pin and the washer 248 may be formed with a transverse slot in which the end of rod 2|4 may seat. A compression coil spring or pull rod spring 258 serves to exert pressure between the bushing 222 and the bushing 228.

The bushing 240 is forked at its rearward end, being divided into two rearward extensions 252 between which a cooking lever or ring trigger 254 is pivotally arranged on a pivot pin 258 extending through matching transverse apertures bored through both extensions 252 of bushing 240and the stud l258 formed on trigger Y254 The rod 2 I4 The r'ing trigger 264 has a rounded projection, the end 255 of which is in any one of a number of radial slots 251 formed in the rearward face of' bushing 226,- and the trigger 254 also-has an opposite elongated arm 253 to which a lanyard is secured through a loop The bore 21|2 of body ||6 has an enlarged for- Ward portion 2|3, a sloping inner surface 2|5 connecting the enlarged forward bore 2|3 with the rest of bore 212. sloping surface 2|5 serves as a cam for tilting the'ring hammer tripper 2|8 into release position. The tripper 2|6 has its forward end or foot 2|9 bearing against and in sliding contact with the inner surface of bore 2| 3 as indicated in Figure 3. The rearward end or nger 266 of tripper 2|6 extends into bore |66 through a slot 262 which connects bores |64 and 212, as shown, a longitudinal slot 223 being cut entirely through one side of bushing 222 to allow end 266 of tripper 2 I3 to pass through the slot.

When the tripper 2|6 is in its forwardmost position as shown in Figure 3, its rearward end 2GB-bears against the sloping surface 2 |6- of ham'- me'r |62". As the lanyard attached to arm 253 of trigger 254 is pulled rearwardly, the effect is to retract the pull rod 215i together with the tripper 2li?. The tripper being in contact with firing'k hammer |62 at sloping surface 216, causes the hammer |82 and stop 266 to be retracted, compressing firing spring |18. As the rearward movement of the tripper continues, the end' 216 of the tripper is carriedagainst sloping surface 2|5Y which: cams the end 2|9 upwardly. rlillois camming causes the tripper 2|8 to be partly rotated eounterclockwise on pivot 226, causing endf 266 to move out of bore |66 and into slot 262. Since end` 260 is thus no longer in contact vwith surface 2||lof the hammer |32, the spring |18 forces the hammer and the stop 266- forwardly. The forward motion of the stop 266 is arrested by contact of its forward ends 264 with surface 268 of. recess |44. However, the ring hammer |62 continues its forward motion, its forward end 262 striking `against the firing pin |34, forcing same forward and firing the primer 13. End 266 of bushing 222 continuously presses shoulder 29| on tripper 2|8 forwardly. When the lanyard attached at 25| is released, the pull rod spring 266 presses the trigger parts into their forward position. again as. shown in Figure 3. Lubrication may be accomplished through a hole as at 6i or, if desired, the parts may be made self-lubricating asin oilless bearings and the like.

'I-he movable housing H6 is raised into firing position and lowered out oi' firing position by means of an operating handle or lever 263 rotatably mounted on a pivot pin 264 passing through aligned bores formed in said lever 263 and in the rtwo side walls 266 and 263 of a bifureated extension of projecting portion 216 of housing 22. If desired, the portion 216 may be 'made removable in any suitable manner, such as by forming a dovetail-shaped elongated' groove or recess ||3 in the abutting side face of stationary housing 22 into which an elongated dovetailshaped extension 212 of projection 216 is insertedand secured' therein by means of a pin or Vset screw 21|r passing throughY the extension 212 and the walls of the grooveV H3, and keying them together.

The lever 263 has an extension or arm 216 the outer end surface 218 of which is curved on an arc drawn with thepivot pin 264l as a As will be explained, the

center. The .abutting side of' movable housing H6 has a recess 28|)- formed therein, the surface portion 282 of which has the same curvature as surface 218. A stud 284- vformed on the forward .face of the outer end of arm 216 extends into' recess 280. Thus, when the handle 263 is given a clockwise movement around pivot 264 fromthe position shown Figure 1 to that shown in Figure 2, the stud' 284 is given a similar motion within recess 280; first riding against the arcuate surface 282 of the recess, and then breaking Contact with. surface 262 and bearing downward against the surface 286 of recess 286; This downward pressure causes the movable housing ||0 to move downward to the position shown in Figure 2 which is the lower limit of movement allowed for housing |0. Torraise the housingl IID tov iiring position shown in Figure l, the lever 263 is given a counterclockwise rotation about pivot 266, being returned to the position shown in Figure 1.

The degree of angular rotation of handle 263 and arm 216 may be limited in any suitable manner such as by means of spring pressed rounded projections 211 and 219 secured to wall 266 and adapted to enter a matching recess formed in the abutting face of arm 216 so the movement ofthe arm 216 is between projections 221 and 219. The arm 263 is then rotated from position of Figure l to that of Figure 2, and back again, the respective positions being easily andv automatically limited in this manner as the matching recess receives and engages either projection 211 or 219.

The angle of trigger 254 may be changed by rotating it to be parallel with any desired slot 261, the arm 253 being pressed forwardly to lift the projection out of the slot 251 prior to rotation to a new slot. This feature is of particular utility in permitting the gunner to change the angular position of the trigger arm 253 for maximum ease in pulling the lanyard from any desired location, and permits him to take advantage of whatever cover is available.

To prevent firing the primer until the breech block of the gun is fully closed, a safety slide 266, carried by the breech block carrier |0, is sl'idably arranged in a groove or recess 268 formed in carrier l0, and is under constant spring pressure biasing its rounded L-shaped end 269 .against the side 210 of movable housing im. As the movable housing ||0 is dropped down from the position shown in Figure 1 to that shown in Figure 2, the end 269 of the safety slide 266. then presses against the sloping surface portion 212 of the housing H6, sliding in groove 268 to keep in contact with the housing. By structure not shown, the safety slide- 266 is locked in the position shown in Figure 2 so long as the breech block of the gun is notv fully closed. Thus, while the breech block of the gun is operi and the firing mechanism is in the position shown in Figure 2, it is possible to insert a primer into the extractor 60, but the movable housing ||IJ cannot be raised into firing position until the breechblock of the gun is fully closed. The firing mechanism is thus provided with an effective safety feature.

For preventing the cap |10, as shown in Figure 3, and the bushing member 228 from accidentally unscrewing out of the housing I0, the construction illustrated in Figure 11 is employed.

This shows a view taken along the line of Figure 7, showing only the surfaces nearest to the line H-IL Thus the radial face 229 of bushing 228 is undercut outside of the starshaped portion enclosed by the lines 23|, each of the latter lines being an arc of a circle `having the same diameter as that of the rearward face of cap 16, and so located that any arc 23|, when moved into the position of arc 233, will be in substantial contact all along its are with the perimeter of cap |10, a small amount of clearance being present. In assembling the parts, the cap is first threaded all the way into its recess until its rearward face is flush with the rearward surface of movable housing H0. The bushing 228, carrying the trigger assembly, is then threaded into its recess all the way, and then turned out again a fraction of a turn until one of the arcs 23| is in the position 233. Then the cap 119 is turned to the left so it backs out of its recess about a turn. In this position, the bushing 228 cannot be rotated due to obstruction from cap |10 and is thus locked in place. The cap |19 cannot accidentally move forwardly out of engagement with the arc 233 because of the rearward pressure of spring |18. Similarly cap |19 cannot move rearwardly due to obstruction of undercut face 229 which overlaps the edge of cap |10.

Although the invention has been described in specific terms, it is to be understood that numerous changes may be made in the; dimensions, shapes, materials and arrangement within the spirit and scope of the invention as claimed.

We claim:

1. In a firing device, a housing, a firing hammer reciprocable in said housing, a pull rod axially reciprocable in said housing, means responsive to axial reciprocation of said pull rod in one direction to retract and subsequently release said hammer, a bushing carried by said housing coaxial of said rod and having circumferentially-spaced radial slots, a trigger lever, a swivel connection between the end of said pull rod extending through said bushing and said lever intermediate its ends, and spring means urging said rod in a direction opposite to said one direction to seat one end of said lever in va selected one of said slots.

2. In a ring device for a cannon, a housing having first and second adjacent parallel bores, a firing hammer reciprocable in said first bore, a rst spring urging said hammer forwardly into firing position, a bushing fixed with said housing coaxial with said second bore, a pull rod reciprocable in said second bore and extending through said bushing, said bushing having a. plurality of circumferentially-spaced slots radial of said rod, means responsive to rearward reciprocation of said pull rod to first retract and then release said hammer, a trigger lever swiveled intermediate its ends to the pull rod adjacent said bushing, one end of said lever being shaped to engage in a selected one of said slots, whereby 10 said pull rod may be reciprooated by said lever in a plurality of angularly related positions thereof radially of said pull rod.

3. In a firing device, a housing, a hammer movable in said housing, means carried externally by said housing and having a plurality of circumferentially-spaced depressions therein concentric of an axis, a pull rod reciprocable in said housing in and along said axis and extending to the exterior of said housing, a :trigger lever, a swivel connection between said lever intermediate its ends and the extending end of said rod, a spring urging said rod forwardly to seat one end of said lever in one said depression, and means operated by reciprocation of said rod in response to a pull on the other end of said trigger lever against the action of said spring, to first move and then release said hammer, said lever being rotatable about the axis of said rod to position its said one end in any selected one of said depressions.

4. In a firing mechanism for cannon, a housing, a pull rod axially reciprocable in said housing and having one end extending exteriorly of said housing, a bushing secured in the wall of said housing concentric of said pull rod, said bushing having a counterbore through the rear face thereof and a plurality of circumferentiallyspaced radial slots concentric of said rod, a sleeve fitting the counterbore of said bushing and having an inwardly-hanged forward end, said one end of said rod having a transverse pin seated on the rear face of said flanged end, a trigger lever, a pivot pin passing through aligned holes in said lever and sleeve, spring means urging said rod forwardly to seat one end of said lever in any one of said slots, and means responsive to reciprocaticn of said rod in response to a pull on the other end of said lever, to lire said cannon.

VVILIJAM SUMMERBELL. LOUIS J. RHEIN. OWEN D. HOOPES.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 90,323 Vavasseur May 18, 1869 240,369 Blake Apr. 19, 1881 370,657 Quick Sept. 27, 1887 610,110 Vickers et al Aug. 30, 1898 800,663 Meigs et al. Oct. 3, 1905 1,080,268 Dawson et al. Dec. 2, 1913 1,303,638 Dawson et al. May 13, 1919 1,310,887 Schneider July 22, 1919 1,865,560 Duffield July 5, 1932 2,311,989 McGill Feb. 23, 1943 2,366,758 Summerbell Jan. 9, 1945 

